U.S. Water News Online
ILWACO, Wash. -- Two highways repaired with chunks of rubber are smoking and oozing a toxic, oily goo that is threatening nearby marshes on the Columbia River. Cleanup is under way to remove the smoldering tires, and halt seepage of toxic substances into surrounding soil and water.
The work is all the more urgent, explained biologist Thom Hooper of the state Department of Fish and Wildlife, because the rubber in each tire contains hydrocarbon compounds equivalent to about a gallon of oil. Meanwhile, the cleanup effort is complicated by the migration of the ocean-bound salmon fingerlings, and the nesting of eagles nearby, Hooper said.
The first sign of trouble came in December, when buried rubber from a million recycled tires began to burn along this 150-foot stretch of rebuilt highway on route 100 -- apparently from natural processes, similar to what heats up a compost pile. The state had used the tires, in place of rock or gravel, to provide 7,000 cubic feet of fill for highway construction.
The burning highway runs atop an embankment above Baker Bay, a pretty inlet at the mouth of the Columbia River. Digging out this toxic stretch of road will cost from $1 million to $3 million.
"There's never been a tire fire under a road," said Joe Zelibor, a former science adviser to the Scrap-Tire Management Council in the Rubber Manufacturers Association. "There's no history of methods to use" for cleanup.
At Ilwaco, the recycled rubber is piled to a maximum depth of 27 feet on a 4-foot gravel bed, topped with 3 feet to 5 feet of soil. In Garfield County, where the repair involved a gully, the tire layer is about 45 feet deep.
Pressure, water, microbes, and the rubber itself are combining to create chemical heat measured at up to 160 degrees at cracks in the road's surface and likely hovering around 450 degrees deep inside the embankment, according to officials.
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